I have a friend that has assassins that are breeding. I wouldn't call it exploding in numbers though. Assassins are a non-hermaphroditic snail, so it does require a male and a female to breed, plus I think they take longer to mature. I think they're really pretty too. I just wish I could keep a crew of 5 or 6 of them alive in my high CO2 environment. I have tiny ramshorns (not on purpose). I feed sparingly and squash any that I see on the glass. Sometimes I'll collect them by hand if I have the time. I've managed to keep them under control so far but I would like to get rid of them all together so I didn't have to worry about them at all.

Of course the Co2 only affects the snails you want to keep. The ramshorns love cucumber. Peel the skin off and slice length wise. You don't have to wait long and it'll be covered! Then carefully scoop it out. Walla! That many less ramshorns

I have Botia kubotai and Golden Dojos in my snail-control tank. They are hilarious fish to watch and they co-exist peacefully with the rest of the fish. They are very sociable, you need at least 3 B. kubotai. 2 Golden Dojos will do fine. What snails?

B. kubotai hide a lot, while Dojo are all over the tank. I bet the kids will love them. You can get them at PetSmart.